Sore mouth and problems with your teeth

The cells lining your mouth are sensitive to radiation. So radiotherapy is likely to make your mouth sore and you might have ulcers after a week or so. This is called oral mucositis.

The soreness usually only lasts while you are having treatment and for a few weeks afterwards. Your doctor, nurse or radiographer can give you painkillers to help. Following a mouthwash routine from the start of radiotherapy will also help.

You might need to have a fine feeding tube into your nose if your mouth is sore and stopping you from eating or drinking properly. The tube is called a nasogastric tube. Or you might have a tube put directly into your stomach through your skin. This tube is called a percutaneous endoscopic gastrostomy tube (PEG tube).

Dry mouth

Your treatment might affect the salivary glands so that they produce less or no saliva. It can be uncomfortable to chew or swallow. Let your radiographer or doctor know if you're having problems. 

After the treatment ends it can take some time for saliva production to get back to normal. If the radiotherapy treatment area includes the salivary glands, you might have a permanently dry mouth afterwards. Your doctor will talk to you about this before you start treatment.

Some of the following tips might help:

  • Ask your doctor to prescribe medicines that stimulate saliva.
  • Sip drinks often to keep your mouth moist.
  • Moisten your food with sauces, gravy, cream, custard or ice cream.
  • Chewing sugarless gum can make your salivary glands produce more saliva.
  • Clean your tongue with a liquid made from a teaspoonful of bicarbonate of soda in a litre of warm water.
  • Use lip balm to keep your lips moisturised.
  • Use moistened cotton wool or a soft toothbrush to clean your tongue.
  • Ask your doctor to prescribe artificial saliva sprays or gels.

Thrush infection

Radiotherapy can also make it easier for infections of the mouth to develop, such as thrush. The radiotherapy team will check your mouth regularly during your treatment.

Let your doctor or nurse know if you have any white patches on the inside of your mouth or on your tongue. They can prescribe medicines to help.

Taste changes

Radiotherapy can also affect your taste buds. You might notice changes in the way your food tastes. Some people say their food has a metallic taste. Others say that all foods taste the same.

There are some tips on making food tastier. You might need to wait to try these until your mouth has recovered from the treatment and is not sore any more.

You could try using more herbs and spices to flavour your food, as well as using strong tasting sauces like sweet and sour. Sharp tasting foods, such as fresh fruit and sharp boiled sweets can be refreshing but only use these after your mouth has healed.

The radiotherapy team can arrange for you to talk to a hospital dietitian for advice about overcoming taste changes.

Problems with your teeth

You visit a dentist before you start radiotherapy to the head and neck. They look for any teeth that might be decaying or already decayed and will remove them. This is because radiotherapy makes it more likely that your teeth will decay so it's best to take them out first to avoid problems. Your mouth will also not heal as quickly after radiotherapy.

You'll also need to go for check ups at the dentist more often. Fluoride treatment might help to protect your teeth. You can have this as a mouthwash to use twice a day. 

Remember to tell your dentist that you have had radiotherapy to your mouth before you have any dental work. Your dentist might need to change the way they treat you. They may also need to talk to your radiotherapy doctor before giving you any treatment.

Things you can do to help

There are some things you can to stop any further irritation to your mouth. These include: 

Eating and drinking

Some food and drinks can irritate your mouth and might be painful to eat. These include: 

  • spicy food
  • alcohol - especially spirits
  • dry food, such as crisps, might scratch your mouth
  • very hot food or drinks

Because of this it can be best to eat a bland diet for a while. And soft foods such as potato and porridge.

Mouth care

A dry, sore mouth is more prone to infection. So your doctor or nurse will give you mouthwashes and a mouth care routine to follow. This helps keep your mouth healthy during your treatment. 

It is important to keep your mouth clean and as healthy as possible. It's best to use a small soft toothbrush to clean your teeth. And you might need to clean them more than twice a day.


Smoking can make the soreness worse. You can try to cut down on smoking. Talk to your radiotherapy team about nicotine replacement treatments to help with this.  


Wearing false teeth (dentures) may make your mouth more sore during radiotherapy. You might find it more comfortable to take them out for some time during the day.

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